Apparatus for applying a gloss to paper in drying thereof



p 21, 1965 E. J. JUSTUS 3,206,869

APPARATUS FOR APPLYING A GLOSS TO PAPER IN DRYING THEREOF Filed D80. 1, 1961 PRESSURE PRESSURE AI Z (APPL Y/NG ROLL ROLL TEMP.

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[dyer dais/ms a w %EYS United States Patent 3,206,869 APPARATUS FOR APPLYING A GLOSS T0 PAPER IN DRYING THEREOF Edgar J. Justus, Beloit, Wis., assignor to Beloit Iron Works, Beloit, Wis., a corporation of Wisconsin Filed Dec. 1, 1961, Ser. No. 156,429 S-Claims. (Cl. 34-113) This invention relates to an improved gloss calender for finishing paper webs and the like.

A principal object of the present invention is to improve upon the finishing and/ or glossing of paper webs by providing improved means to heat the finishing roll of a gloss calender.

A further object of the invention is to shorten the warm up period of the finishing roll of a gloss calender by heating the finishing roll by the impingement of heated air directly on the outer periphery of the roll.

Still another object of the invention is to improve upon the calenders heretofore in use for the glossing of paper webs, by providing a drier hood wrapped about a portion of a finishing roll of a calender and arranged to impinge heated air directly on the finishing roll across the width of the roll in accordance with the requirements for heat.

A further object of the invention is to improve upon and make it possible to heat the finishing roll of a calender to a higher temperature than formerly by directing high velocity and high temperature air directly on the surface of the finishing roll of a calender on the incoming side of the nip between the backing roll and finishing roll to thereby uniformly heat the outer surface of the finishing roll throughout a substantial area thereof, dependent upon the required temperature for finishing the paper web.

A still further object of the invention is to provide better caliper control in the finishing of paper webs by heating the finishing roll to higher temperatures than formerly by the impingement of air directly on the finishing roll in accordance with the requirement for heat across the surface thereof.

These and other objects of the invention will appear from time to time as the following specification proceeds and with reference to the accompanying drawing wherein:

FIGURE 1 is a diagrammatic view of a gloss calender illustrating the heating of the finishing roll in accordance with the principles of the present invention;

FIGURE 2 is a diagram generally illustrating the principles of supplying heated air for impingement directly on the finishing roll; and

FIGURE 3 is a diagrammatic sectional view through a form of resilient backing roll that may be used in carrying out the principles of the present invention.

In the embodiment of the invention illustrated in FIG- URE l of the drawings, I have shown a calender apparatus for finishing a web of paper W, which may be uncoated paper or coated paper, in which finishing or glossing is attained by the process of pressing the fibers of the web to the web, and in effect ironing the web as it leaves the drier. The calender of the present invention is ordinarily used to calender uncoated paper as it leaves the paper making machine, but may advantageously be used to calender sized printing grades of paper or board grades of paper.

As diagrammatically shown in FIGURE 1 of the drawings, the calender or glossing apparatus includes a relatively large diameter finishing roll 11 having a highly polished finishing surface, and a pair of hard surfaced but resilient backing rolls 12 and 13 suitably pressed into engagement with the finishing roll 11, to define calendering nips between said back up rolls and said finishing roll, pressing the traveling web into engagement with said finishing roll at points, which are shown in FIGURE 1 as 3,206,869 Patented Sept. 21, 1965 being diagrammatically spaced apart, but which may be of any desired angular spaced relation with respect to each other. The nip between the rolls 11 and 12 may serve to press and level out the sheet while the nip between the rolls 11 and 13 may serve to further press the sheet and place the required finish thereon.

The web passes through the nip defined by the backing roll 12 and finishing roll 11 downwardly along anidler roll 14, across the bottom of the finishing roll 11, under and upwardly of an idler roll 15, to and through the nip between the finishing roll 11 and backing roll 13, from which it may pass in its finished form to a winding reel (not shown).

The finishing roll 11 is a driven roll and may be driven from a suitable source of power in a conventional manner (not shown) and may have a plated surface, plated with chrome or nickel, to provide a highly polished surface for the glossing treatment.

The backing rolls 12 and 13 may comprise a metal core having a resilient cover made from rubber or other material, providing a hard but resilient surface (FIGURE 3). The backing rolls 12 and 13 are driven by contact with the web W and the finishing roll 11, although it should be understood that said backing rolls may be positively driven under certain operating conditions.

It should further be understood that while the backing rolls 12 and 13 have resilient surfaces, that the surfaces need not necessarily be resilient, but may be metal surfaces.

The backing rolls 12 and 13 may be loaded hydraulically or pneumatically, in a conventional manner, to hold the exacting nip pressures, particularly on high-speed machines, which pressures may be controlled automatically in accordance with the condition of the web being run, in a manner which is no part of the present invention so need not herein be shown or described further.

In conventional calendars, the finishing roll has been heated internally by steam to temperatures to bring the outer surface of the roll substantially to the temperature of the boiling point of water. Due to limitations in the thickness the shell of a finish roll that will withstand the heavy pressures of calendering, it is not economical to internally heat a finish roll by steam to temperatures much above the temperature of the boiling point of water. It has been found, however, that calendering may advantageously be attained at far higher temperatures than the boiling point of water and at temperatures as high as 450 and that where calendering is attained at these temperatures, not only is the product improved and more economically produced, but the number of drier rolls in the paper machine may also be substantially reduced.

In accordance with the principles of the present invention, I am able to attain these temperatures by the use of a drier hood 16 impinging heated air directly on the uncovered surface of the finishiing roll 11 throughout an area of the roll, dependent upon the required temperature of the surface of the roll.

As, for example, for a wrap of a drier hood of 156 about a finishing roll, like the roll 11 and an air temperature of 600 F. within the hood, the temperature of the surface of the finishing roll may be maintained at 450.

The wrap required to maintain the temperature of the surface of the finishing roll 11 at 400 F., with a drier temperature of 600 F. within the hood is 108, while the wrap required to maintain the temperature of the surface of the finishing roll 11 at 350 with a drier temperature of 600 F. within the hood is substantially 76.

The dried hood 16 is diagrammatically shown in FIG- URE 2 as being. connected with a source of heated air under pressure through an inlet conduit 17. Said drier hood has a bottom surface 19, spaced from and generally conforming to the periphery of the finishing roll 11 and wsrapped therearound between the backing rolls 12 and 1 The hood or air cap may be of a type similar to that shown and described in application Serial No. 808,237 for Web Moisture Profile Control for Paper Machines, filed April 22, 1959, by Robert A. Daane and Edgar J. Justus, U.S. Patent No. 3,089,252 and generally has a perforate bottom forming impingement nozzle impinging heated air on the surface of the finishing roll 18 throughout the area of the bottom 19 of the hood 16 and zoned to provide a plurality of plenum chambers communicating with the perforate bottom of the hood, to enable the distribution of heated air across the width of the roll to be varied under the control of air distribution valves and ducts (not shown) controlling the distribution of heated air throughout the width of the finishing roll, to maintain the profile of the roll uniform, and to not only provide improved caliper control of the web, but also to more efficiently finish the web. I The hood or fair cap 16 is no part of the present invention so need not herein be shown or described in detail, except to point out that a fan or air blower 20, which may be on the outside of the hood, is provided to force air through a heater 21 and into the drier hood, for impingement on the surface of the roll in accordance with the requirements for heat, to not only heat, but to also control the profile of the roll and improve the caliper of the web.

In FIGURE 2, I have also shown a temperature controller 25, controlling the temperature of the heater 21 in accordance with the temperature of the air entering the hood or air cap 16, to assure the impingement of heated air onto the finishing roll 11 at a uniform temperature throughout the calendering operation.

It may be seen from the foregoing that by the simple operation of wrapping a drier hood about the finishing roll 11 and impinging heated air directly on the uncovered surface of the finishing roll throughout the area of the hood wrapped about the finishing roll, that the finishing roll may be efiiciency heated to temperatures substantially higher than have heretofore been used to effect calendering, and sufficiently high to take the place of the final drying rolls in the drier of the paper making machine.

It may further be seen that by the calender of the present invention, the finishing roll may be more efficiently heated than formerly, at higher temperatures than have heretofore been used, and the time required to warm up the calender roll may be materially reduced.

It may still further be seen that the heated air impinged on the outer surface of the finishing roll may be distributed along the surface of the roll to not only heat the roll to higher temperatures than have heretofore been considered to be practical, but also to maintain the surface of the roll uniform with a resultant improved caliper control of the web.

While I have herein shown and described one form in which my invention may be embodied, it may readily be understood that various variations and modifications in the invention may be attained without departing from the spirit and scope of the novel concepts thereof.

I claim as my invention:

1. In an apparatus for finishing paper web materials,

(a) a hard surfaced finishing roll adapted for contact with the web,

(b) at least one resilient pressure applying backing roll in nip defining relation with said hard surfaced finishing roll,

(c) and means for heating the periphery of said hard surfaced finishing roll to a temperature sufficiently high to complete the drying of the paper web and finish the web in the nip between said rolls, said heating means comprising (d) a drier hood wrapped about a portion of the surface of said finishing roll on the incoming side of the nip between said pressure applying backing roll and said hard surfaced finishing roll and impinging heated air directly on the surface of said finishing roll on the incoming side of said nip.

2. A calender comprising (a) a hard surfaced finishing roll,

(b) at least one pressure applying backing roll in nip defining relation with said finishing roll,

(c) an idler roll spaced from said backing roll on the outgoing side of the nip between said backing roll and hard surfaced finishing roll,

((1) and means impinging heated air directly on the surface of said hard surfaced finishing roll over a substantial area thereof comprising a hood extending along said finishing roll on the incoming side of the nip between said finishing roll and said backing roll and having a bottom surface generally conforming to said finishing roll.

3. A calender comprising (a) a hard surfaced finishing roll,

(b) first and second circumferentially spaced pressure applying rolls in nip defining relation with said finishing roll,

(c) an idler roll spaced from said backing roll on the outgoing side of the nip between said backing roll and said hard surfaced finishing roll,

((1) a hood extending along said hard surfaced finishing roll in the space between said pressure applying rolls and on the incoming side of the nip between said first pressure applying roll and said hard surfaced finishing roll and generally conforming to said finishing roll and impinging heated air directly on the incoming surface of said finishing roll throughout the Width thereof.

4. In an apparatus for finishing paper web materials,

(a) a hard surfaced finishing roll adapted for contact with the web,

(b) two resilient faced pressure applying backing rolls in nip defining relation with said hard surfaced finishing roll, spaced circumferentially along the surface of said finishing roll,

(c) means guiding a paper web to pass between first one nip and then the second nip defined by said finishing and backing rolls,

(d) and means for heating the periphery of said hard surfaced finishing roll for a substantial area thereof along the incoming side of the nip between 2111 11!- coming backing roll and said hard surfaced finishing roll at a temperature sufficiently high to complete the drying of the paper web and finish the web in the hips between'said backing and finishing rolls, said heating means comprising (e) a drier hood extending for substantially the width of said finishing roll and wrapped around a portion of the circumference thereof and impinging heated air directly on the surface of said finishing roll 5. In an apparatus for finishing paper web materials,

(a) a hard surfaced finishing roll adapted for contact with the web,

(b) first and second spaced circumferentially finishing roll and in nip finishing roll,

(0) two idler rolls spaced from said finishlng roll at the outgoing side of the nip between said first pressure applying backing roll and said finishing roll and at the incoming side of the nip between said second pressure applying backing roll and said hard surfaced finishing roll,

(d) means for heating the periphery of said hard surfaced finishing roll between the outgoing side of the nip between said second pressure applying backing roll and said hard surfaced finishing roll and the inpressure applying backing rolls along the surface of said defining relation with said coming side of the nip between said first pressure applying backing roll and said hard surfaced finishing roll to a temperature sufiiciently high to complete the drying of the paper Web and to finish the web in the nips between said first and second pressure applying backing rolls and said hard surfaced finishing roll, said heating means comprising,

(e) a drier hood extending over said finishing roll for substantially the width thereof and wrapped about a portion of the circumference thereof and extending between said second and first pressure applying backing rolls on the incoming side of the nip between roll and impinging heated air directly on the surface of said finishing roll over a substantial area thereof.

References (Iited by the Examiner UNITED STATES PATENTS 1,660,640 2/28 Asten 34111 X 2,099,160 11/37 Charch 34-414 X 2,784,652 3/57 Hornbostel 34111 X 2,909,847 10/59 Hornbostel et al. 34-111 X FOREIGN PATENTS 727,058 3/55 Great Britain.

NORMAN YUDKOFF, Primary Examiner.

said first pressure applying roll and said finishing 1 CHARLES OCQNNELL, E i 

1. IN AN APPARATUS FOR FINISHING PAPER WEB MATERIALS, (A) A HARD SURFACED FINISHING ROLL ADAPTED FOR CONTACT WITH THE WEB, (B) AT LEAST ONE RESILIENT PRESSURE APPLYING BACKING ROLL IN NIP DEFINING RELATION WITH SAID HARD SURFACED FINISHING ROLL, (C) AND MEANS FOR HEATING THE PERIPHERY OF SAID HARD SURFACED FINISHING ROLL TO A TEMPERATURE SUFFICIENTLY HIGH TO COMPLETE THE DRYING OF THE PAPER WEB AND FINISH THE WEB IN THE NIP BETWEEN SAID ROLLS, SAID HEATING MEANS COMPRISING (D) A DRIER HOOD WRAPPED ABOUT A PORTION OF THE SURFACE OF SAID FINISHING ROLL ON THE INCOMING SIDE OF THE NIP BETWEEN SAID PRESSURE APPLYING BACKING ROLL AND SAID HARD SURFACED FINISHING ROLL AND IMPINGING HEATED AIR DIRECTLY ON THE SURFACE OF SAID FINISHING ROLL ON THE IMCOMING SIDE OF SAID NIP. 